Michael Ross wrote:
I have an Amrel programmable power supply 4A, 60V. Very handy for Li-ion.
I am a lead acid dunce. Can I imitate a smart charger with the Amrel
power supply?
Yes, if you supply the "smarts" (i.e. manually control it).
Are there different protocols for conventional, AGM and Gel? I assume so.
Yes. all lead-acids are similar, but there are minor differences between
flooded, AGM, and gel.
You can find lots of information (way too much, in fact) on charging
them online, in books, and from clueless old mechanic's gossip.
Lead-acids have been around for so long that there are a million
opinions on how to charge them!
But here are the basics. The exact voltages will depend on the type of
battery, its temperature, age, and condition. For best results, see the
manufacturer's recommendations. (Which by the way, tend to err on the
high side, and only apply when the battery is brand new).
1. Bulk:
Charge them at as high a current as you like until the voltage reaches
the gassing point; about 2.25-2.3v per cell. The battery doesn't care;
the charger is what usually limits the current in this step. At this
point, the battery is about 80% charged.
2. Absorption:
Now limit the voltage to around 2.4v/cell (14.4v for a 12v battery). The
current will fall as the battery continues to charge. The battery is
100% charged when the current stops falling, or falls under 2% of the
battery's amphour capacity (like 1 amp for a 50 amphour battery).
3. Finish, or Equalization (optional):
Continue charging at very low current, like 1% to 2% of the battery's
amphour capacity, and let the voltage keep rising. End when:
- the voltage reaches 2.5v/cell (15v for a 12v battery),
- or the voltage stops rising,
- or 1 to 2 hours has elapsed.
This step isn't necessary on every charge cycle. Do it as needed. Wait
at least 8 hours after charging, then measure the voltages between
batteries (or cells, if you can get at them). Do step 3 if the highest
and lowest differ by more than 1%.
--
If we knew what we were doing, it wouldn't be called research, would it?
-- Albert Einstein
--
Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm
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